/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.naming.factory;

import java.util.Hashtable;
import javax.naming.Name;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.naming.Reference;
import javax.naming.RefAddr;
import javax.naming.spi.ObjectFactory;
import org.apache.naming.EjbRef;

/**
 * Object factory for EJBs.
 * 
 * @author Remy Maucherat
 * @version $Id: EjbFactory.java 939511 2010-04-29 23:48:20Z kkolinko $
 */

public class EjbFactory implements ObjectFactory {

	// ----------------------------------------------------------- Constructors

	// -------------------------------------------------------------- Constants

	// ----------------------------------------------------- Instance Variables

	// --------------------------------------------------------- Public Methods

	// -------------------------------------------------- ObjectFactory Methods

	/**
	 * Crete a new EJB instance.
	 * 
	 * @param obj
	 *            The reference object describing the DataSource
	 */
	public Object getObjectInstance(Object obj, Name name, Context nameCtx,
			Hashtable environment) throws Exception {

		if (obj instanceof EjbRef) {
			Reference ref = (Reference) obj;

			// If ejb-link has been specified, resolving the link using JNDI
			RefAddr linkRefAddr = ref.get(EjbRef.LINK);
			if (linkRefAddr != null) {
				// Retrieving the EJB link
				String ejbLink = linkRefAddr.getContent().toString();
				Object beanObj = (new InitialContext()).lookup(ejbLink);
				// Load home interface and checking if bean correctly
				// implements specified home interface
				/*
				 * String homeClassName = ref.getClassName(); try { Class home =
				 * Class.forName(homeClassName); if (home.isInstance(beanObj)) {
				 * System.out.println("Bean of type " +
				 * beanObj.getClass().getName() + " implements home interface "
				 * + home.getName()); } else {
				 * System.out.println("Bean of type " +
				 * beanObj.getClass().getName() +
				 * " doesn't implement home interface " + home.getName()); throw
				 * new NamingException ("Bean of type " +
				 * beanObj.getClass().getName() +
				 * " doesn't implement home interface " + home.getName()); } }
				 * catch (ClassNotFoundException e) {
				 * System.out.println("Couldn't load home interface " +
				 * homeClassName); }
				 */
				return beanObj;
			}

			ObjectFactory factory = null;
			RefAddr factoryRefAddr = ref.get(Constants.FACTORY);
			if (factoryRefAddr != null) {
				// Using the specified factory
				String factoryClassName = factoryRefAddr.getContent()
						.toString();
				// Loading factory
				ClassLoader tcl = Thread.currentThread()
						.getContextClassLoader();
				Class factoryClass = null;
				if (tcl != null) {
					try {
						factoryClass = tcl.loadClass(factoryClassName);
					} catch (ClassNotFoundException e) {
						NamingException ex = new NamingException(
								"Could not load resource factory class");
						ex.initCause(e);
						throw ex;
					}
				} else {
					try {
						factoryClass = Class.forName(factoryClassName);
					} catch (ClassNotFoundException e) {
						NamingException ex = new NamingException(
								"Could not load resource factory class");
						ex.initCause(e);
						throw ex;
					}
				}
				if (factoryClass != null) {
					try {
						factory = (ObjectFactory) factoryClass.newInstance();
					} catch (Throwable t) {
						NamingException ex = new NamingException(
								"Could not load resource factory class");
						ex.initCause(t);
						throw ex;
					}
				}
			} else {
				String javaxEjbFactoryClassName = System.getProperty(
						"javax.ejb.Factory", Constants.OPENEJB_EJB_FACTORY);
				try {
					factory = (ObjectFactory) Class.forName(
							javaxEjbFactoryClassName).newInstance();
				} catch (Throwable t) {
					if (t instanceof NamingException)
						throw (NamingException) t;
					NamingException ex = new NamingException(
							"Could not create resource factory instance");
					ex.initCause(t);
					throw ex;
				}
			}

			if (factory != null) {
				return factory.getObjectInstance(obj, name, nameCtx,
						environment);
			} else {
				throw new NamingException("Cannot create resource instance");
			}

		}

		return null;

	}

}
